Papers by Author: Guo Ping Chen

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Authors: Guo Ping Chen, Takashi Ushida, Tetsuya Tateishi
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Authors: Guo Ping Chen, Daisuke Akahane, Naoki Kawazoe, Yoshio Shirasaki, M. Tanaka, Katsuyuki Yamamoto, Tetsuya Tateishi
Abstract: A novel collagen sponge that can protect cell leakage during cell seeding was developed by wrapping all the surfaces except the upside of a collagen sponge with membrane that has pores smaller than cell. The collagen sponge was used for three-dimensional culture of human bone marrow-derived mesenchymal stem cells (MSCs). The cells adhered to the collagen, and proliferated to fill the spaces in the sponge. The cell seeding efficiency was higher than 95%. The MSCs cultured in the collagen sponge in the chondrogenic induction medium supplemented with TGF-β3 and BMP6 expressed genes encoding type II collagen, SOX9 and aggrecan. HE staining indicated the round morphology of differentiated cells and the extracelluler matrices were positively stained by safranin O and toluidine blue. Type II collagen and cartilage proteoglycan were detected by immunostaining with anti-type II collagen and anti-cartilage proteoglycan. These results suggest the chondrogenic differentiation of MSCs. The collagen sponge facilitated cell seeding and chondrogenic differentiation of MSCs, and will be useful for cartilage tissue engineering.
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Authors: Takashi Ushida, Tamotsu Tamaki, Guo Ping Chen, Yoshikazu Umezu, Tetsuya Tateishi
733
Authors: Yu Jiang Fan, Guo Ping Chen, M. Tanaka, Tetsuya Tateishi
Abstract: Polyamides containing amino acid residues were synthesized through a chemoenzymatic route. At first, monomers containing amino acid esters at both ends were prepared from amino acid esters and bifunctional acid chlorides through a Scotten-Baumann reaction under organic condition. Diamine was used as bifunctional nucleophilic reagent to aminolysis the amino acid ester bonds of these monomers under protease catalysts, leading to the polycondensation to form the desired polyamides containing amino acid residues. Spectra characterizations confirmed the structure of obtained polyamides. The factors that influence the polymerization, including the type of enzymes, the amount of enzymes, and the water contents in the solvent, were also discussed. It is expected that the obtained polyamides have the potential for biomaterial applications.
469
Authors: Tetsuya Tateishi, Guo Ping Chen
Abstract: A new method for the preparation of biodegradable porous scaffolds has been developed by using preprepared ice particulates as porogen material. A novel kind of hybrid biodegradable porous scaffold has been developed by forming collagen microsponges in the pores or interstices of a synthetic polymer sponge or mesh. A hybrid sponge of synthetic polymer, collagen and hydroxyapatite has been developed for hard tissue engineering. Bovine articular cartilage-like tissue has been engineered by culturing chondrocytes in the PLGA-collagen scaffolds.
59
Authors: Toru Tonegawa, Toshiyuki Ikoma, Tomohiko Yoshioka, Guo Ping Chen, Nobutaka Hanagata, M. Tanaka
Abstract: The adsorption properties of metal ions containing hydroxyapatite (Ca10(PO4)6(OH)2, HAp) were elucidated for the development of protein drug carrier. As-prepared metal ion containing HAp nanocrystal showed plate-like morphology with 10-20nm in length and 5-10nm in width. The metal ion containing HAp microparticles had higher specific surface area than the HAp microparticle. The adsorption amount per unit area of HAp showed higher than those of metal ion containing HAp. The adsorption behavior followed the Langmuir curves for each protein, indicating the monolayer adsorption. The loaded amount of proteins could be one of the most important properties for the application of drug delivery carrier.
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Authors: Toru Tonegawa, Toshiyuki Ikoma, Guo Ping Chen, M. Tanaka
Abstract: Control of protein release without the initial burst from zinc containing hydroxyapatite porous microparticles (Zn-HAp) was investigated with a novel formulation method. The formulation method was a coat of polyL(L-lactide; PLA) on the microparticle with nano-thickness, which obviously suppressed the initial burst of protein release compared with the microparticles without the formulation, the coat of PLA. The HAp/PLA microparticle with 1-20μm of the size distribution was available for the drug delivery carrier of proteins without the degradation.
857
Authors: Li Guo, Yu Jiang Fan, Naoki Kawazoe, Guo Ping Chen, M. Tanaka, Tetsuya Tateishi, Xing Dong Zhang
Abstract: In this study, three kinds of photo-reactive polymers, namely positively charged azidophenyl-derived polyallylamine (AzPhPAAm), negatively charged azidophenyl-derived poly(acrylic acid) (AzPhPAAc) and neutral azidophenyl-derived poly(ethylene glycol) (AzPhPEG), were synthesized by introduction of photo-reactive group (-N3) into polyallylamine, poly(acrylic acid) and poly(ethylene glycol), respectively. The structure of the azidophenyl-derived polymers was confirmed by 1H-NMR measurement. All of the photo-reactive polymers can be pattern-grafted on the surface of cells culture plate, which was confirmed by the optical microscopy observation. The contact angle decreased after surface modification by the photo-reactive polymers. Human mesenchymal stem cells (MSC) cultured on the modified surfaces showed different morphology. The cells adhered and spread more on the PAAm- and PAAc-grafted surfaces than on the PEG-grafted surface. The pellets formed on PAAm- and PEG-grafted surfaces in condrogenic differentiation medium were positively stained by safranin O/ fast green. But the pellet formed on PAAc-grafted surface did not show obviously positive staining for safranin O/ fast green. These results indicate that the PAAm- and PEG-grafted surfaces promoted chondrogenic differentiation of MSC.
1189
Authors: Hajime Watanabe, Toshiyuki Ikoma, Guo Ping Chen, M. Tanaka
Abstract: Time-controlled releases of proteins from hydroxyapatite/chondroitin sulfate (HAp/ChS) spherical microparticles were achieved by the addition of zinc cation into the mixture solutions of HAp/ChS and protein as a novel formulation. The initial bursts of proteins, such as cytochrome c and bovine serum albumin, were apparently suppressed by the amount of zinc cation, which could be attributed to the formation of coordinate bonds of zinc cation among proteins and/or ChS moleculars. The increase of molecular lengths of ChS chains decreased the adsorbed amount of proteins, which did not apparently affected to the release of proteins.
1009
Authors: Hajime Watanabe, Toshiyuki Ikoma, Guo Ping Chen, Akira Monkawa, M. Tanaka
Abstract: Hydroxyapatite/chondroitin sulfate (HAp/ChS) microparticles with the perfectly spherical shape and the averaged particle sizes of 4.1, 7.8, 19.9 and 29.4 µm were fabricated by a spray dry method under the different atomizing pressures and the concentrations of suspensions. The contents of ChS in the microparticles were varied at 1.49, 3.18, 7.82, 14.2 wt%, and the ChS elution rate in distilled water from the microparticles was increased with the increase of ChS contents. The adsorption isotherms of cytochrome C on the microparticles in 1/10 diluted phosphate buffer saline (PBS) were followed to the Langmuir’s equation regardless of the change of ChS contents, while those of catalase were not followed. The HAp/ChS microparticles can adsorb greater amount of cytochrome C than pure HAp microparticles, but less amount of catalase than pure HAp. The electrostatic interaction between the proteins and ChS was of great importance in the adsorption properties.
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